While retinoblastoma is diagnosed in only 350 children annually in the United States (and at similar rates worldwide), the standard cure is often physically and emotionally traumatic: the removal of one or both eyes and the optic nerve. But an experimental intra-arterial delivery system, which injects high-dose chemotherapy directly into the ocular tumor may not only save the eye, but the vision as well.
At least 10 children have participated in clinical trials at Memorial Sloan-Kettering and New York-Presbyterian Hospitals, both in New York. Dr. David H. Abramson, Chief of the Ophthalmic Oncology Service at MSK, says he and his colleague Dr. Pierre Gobin of NewYork Presbyterian are now performing the procedure on a weekly basis.
Standard treatment for retinoblastoma, which often occurs in children under the age of two, is six-to-nine months of chemotherapy to shrink the ocular tumor until it is small enough to be extracted. Doctors often opt to remove the entire eye (enucleation) to insure all of the cancer has been removed, resulting in a cure rate of up to 95%.
But the new procedure, which the doctors are calling ‘chemosurgery’ may spare the eye. A catheter described by Dr. Abramson as about “half the thickness of a string of angel hair pasta” is inserted into the groin, threaded up the vessels in the chest, up into the carotid artery and finally the patient’s ophthalmic artery. Once there, an extremely high concentration of a chemotherapeutic agent, in this case, melphalan (Alkeran), is delivered directly to the retina. “There’s only one blood vessel that supplies all of the blood to the eye,” Dr. Abramson says, “so, unlike some other tumors, it is a blood supply we can control.”
Dr. Abramson acknowledges he was ‘grateful’ to discover that, not only did just a teaspoon of melphalan do the trick, but it stuck only to the cancer cells in the retina with no toxicity to surrounding areas of healthy tissue and, in some cases, saved or even restored vision in the affected eye.
“If these trials are successful, intra-arterial chemotherapy may replace enucleation for the majority of retinoblastoma cases,” Dr. Abramson says. “That would be a revolutionary improvement in the treatment of this disease.”